Military parachutists and other skydivers may use handheld or wearable navigation systems to plan their missions and navigate to their destinations. Such navigation systems have certain operating modes designed to assist mission planning while a user is in an aircraft on the way to a jump point (e.g., the “aircraft modes”), and other operating modes to assist navigation after the user has jumped from the aircraft (e.g., the “descent modes” and the “ground modes”).
Informational needs of the user change significantly at the moment of the jump (i.e., the jump transition). Before the jump, the user needs information for determining the location of a high altitude release point (the “HARP” or “jump point”), the time when the HARP is approached, and the time when the HARP is reached. After the jump, while the user is in freefall or on canopy, the user requires real-time location, ground speed, wind speed and direction, and other informational aids for navigation and situational awareness.
The jump transition also coincides with a peak in the physical and cognitive workload of the user, who at that time is occupied with stabilizing freefall, and deploying and establishing control of the parachute canopy. Because the user is so busy during the jump transition, it is undesirable for the navigation system to add to the user's workload.